REXUS and BEXUS

A REXUS research rocket mounted on the launch pad ready for lift-off. Credit: DLR

The German-Swedish Student Program

The REXUS/BEXUS program (Rocket and Balloon Experiments for University Students) provides students with opportunities to perform scientific and technical experiments on rockets and balloons under specific atmospheric conditions.

Students experience the full life cycle of a space project, which begins with an idea and a planning phase and ends with the publication of its results. In between, the students build and test their experimental equipment, take an active part in the rocket or balloon launch campaign, conduct their experiments, and evaluate the data acquired. They stick to a time schedule with fixed milestones. The duration of the REXUS and BEXUS experiment projects is about 18 and twelve months, respectively.

Every year two REXUS rockets are launched in March and two BEXUS balloons in September. The rockets traverse three atmospheric layers - namely the tropo-, meso- and stratosphere - reaching the thermosphere at an altitude of about 100 kilometers. For stabilization they rotate around their longitudinal axis.

On demand the rockets can be equipped with a yo-yo system which decelerates the spin during the free-flight phase so that experiments can be carried out in reduced gravity, too. Up to five minutes of experiment time are available during the ballistic flight of a rocket, the reduced gravity phase lasting about 90 seconds.

The flights of the BEXUS stratospheric balloons are not actively controlled. Free floating they reach an altitude of around 35 kilometers. Their flight time and thereby, the available length of experiment time varies between two and five hours depending on wind.

Throughout their project cycle, the German participants will be supervised and supported by the DLR Space Administration in Bonn and the DLR Institute of Space Systems in Bremen. Furthermore students will collaborate with EuroLaunch, a co-operation between the Swedish Space Corporation (SSC) and the DLR's mobile rocket base (MoRaBa) in Oberpfaffenhofen,. EuroLaunch handles the rocket and balloon launches at the Esrange space center near Kiruna in Sweden.

The REXUS/BEXUS students' program is realized under a bilateral Agency Agreement between the DLR Space Administration and the Swedish National Space Board SNSB. Fifty percent each of the rocket and/or balloon payloads is available to German and Swedish students, respectively. SNSB has made its share available to students from the other ESA member and cooperating states.

Annually in September the two space agencies release a call for proposals for the BEXUS flights in the subsequent year, and REXUS flights in the year after that.